BAMBARI, Central African Republic, May 24 (Reuters) - French peacekeeping troops in Central African Republic using helicopter gunships and mortars fought Muslim rebels on Saturday at a bridge in the town of Bambari northeast of the capital Bangui, a Reuters witness said.

Photographer Goran Tomasevic said he saw at least five people injured, four of them fighters of the mostly-Muslim rebel Seleka coalition, who have been resisting attempts by the French forces to disarm them.

The French soldiers, deployed as part of the "Sangaris" peacekeeping operation in the conflict-torn former French colony, had used stun grenades to try to disperse machete-wielding civilians who blocked the bridge, but then came under fire from automatic weapons and rocket-propelled grenades.

They brought in at least two helicopter gunships and fired mortars.

On Thursday, French forces in Bambari came under fire after they tried to disarm the Seleka rebels, who have their headquarters at the town and still control the northeast of the country after being driven from Bangui. At least one person was killed.

Muslims in Bambari are unwilling to give up their weapons after similar moves in the capital Bangui led to attacks on Muslims there.

Central African Republic descended into chaos after Seleka rebels seized power in March last year and their attacks on the majority Christian population set off a wave of reprisals.

The Seleka coalition was forced to relinquish power under international pressure in January. Since then, Christian militias known as "anti-balaka" have mounted widespread attacks on Muslims.

More than 2,000 people have been killed in the violence and a million of the country's 4.5 million people have been forced from their homes despite the presence of several thousand African peacekeepers and European Union and French troops. (Reporting by Goran Tomasevic; Editing by Pascal Fletcher)